Formation Of Cu-based Bulk Metallic Glass And Structural Research Of Pd-based Metallic Glass

Since the first report of successful preparation of metallic glasses by P.Duwez at al. in Caltech, the materials have attracted increasing interests due to their unique mechanical, magnetic, electrical and chemical properties. In recent years, Cu-based metallic glass have attracted widely attention since its low price, excellent glass forming ability and good mechanical properties. As one of earliest developed metallic glass, the biggest diameter of Pd-based metallic glass is above 70cm.These two systems are mainly focused in our work. The details of our research are listed as follows: 1. Investigated the thermal stability and glass forming ability of Cu45Zr48-xAl7REx,(RE = La, Ce, Nd and Gd, 0 ≤x ≤ 5 at.%),found out the Cu45Zr46Al7Gd2 with thebest GFA is off-eutectic composition.The y parameter was induced to judge GFA. 2. Adding a small amount of rare-earth element into Cu-Zr-Al system and obtainedthe 10mm diameter composition Cu45Zr46Al7Gd2, indicating the micro-alloyingcan enhance the glass forming ability.3. Investigated the absorbing oxygen ability of the rare-earth elements. The adding of rare-earth elements can be useful to scanvage oxygen from system. In this kind of view, it is possible to develop bulk amorphous alloys in low-vacuum environment4. The mechanical properties of Cu-Zr-Al-RE were studied.The Cu45+xZr48Al7-x(x=1,2,3) have good plasticity.The effect on mechanical properties with different fabrication technics were studied.The different microstructure caused by different technics is supposed to main reason for different mechanical properties.5. Pd40Ni40P20, Pd40Cu30Ni10P20 were investigated by synchron radiation. The intensity of S(Q) has a sudden change of slope with the increasing of temperature. This point is corresponding glass transition temperature.6. The total distribution function of Pd-based metallic glass was obtained by MCGRsoftware. The result of neighbour structure of Pd40Ni40P20 and indicating the Pd-based metallic glass possess the five-folded icosahedron which led to good glass forming ability. With the adding of Cu, the atomic packing density was increased, which is one of the reason for the better GFA of7. Crystallization process of Pd40Ni40P20 was studied by in-situ synchron radiation. The whole process can be divided into two stages.The first stage occurred at nearly 670K and crystall phase was increased at 830K till all of the amorphous turn to crystall.8. The neighbour atomic structure of Pd40Ni40P20 was simulated by Reverse Monte Carlo simulation method. The partial radial distribution function, atom configuration and angle distribution were obtained.